Carbon quantum dots-based fluorescent layered double hydroxide for targeted drug delivery application

Layered double hydroxides (LDHs) are a class of layered materials that have received great attention as drug delivery carriers due to their excellent properties such as biocompatibility, chemical stability, easy synthesis, anion exchange capacity, and controlled drug release. In this research, LDH nanosheets based on Ca and Al were synthesized by a coprecipitation method. The LDH nanosheets were in situ coated by polyethylene glycol (PEG). The LDH nanosheets were decorated with carbon quantum dots (CQDs) derived from citric acid by a hydrothermal method and targeted with folic acid. Doxorubicin hydrochloride (DOX) was used as a model drug to investigate the drug loading and release of the fluorescent LDH. XRD analysis showed that the content of PEG in the synthesis medium affects the crystallinity of the LDHs. FTIR analysis confirmed the successful attachment of CQDs and folic acid (FA) on LDH nanosheets. The fluorescence of the synthesized nanohybrid was influenced by the CQDs content. UV–Vis spectroscopy showed the DOX can be loaded on the nanohybrid with a loading efficiency of 32 %. The drug release of the nanohybrid is pH-dependent. The drug can be released up to 83 % within 12 h in the acidic environment while the release reaches 63 % in the physiological pH at the same time. The synthesized CQDs can be used as pH-dependent fluorescent and targeted nanocarriers in drug delivery systems.